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Purpose: The possibility of vitreal macrophages playing an angiogenic role in oxygen-induced retinopathy (OIR) was investigated. Oxygen-induced retinopathy was produced in newborn animals with the purpose of modeling the proliferative... more
Purpose: The possibility of vitreal macrophages playing an angiogenic role in oxygen-induced retinopathy (OIR) was investigated. Oxygen-induced retinopathy was produced in newborn animals with the purpose of modeling the proliferative phase of human ...
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The international classification of acute retinopathy of prematurity (ROP) appearing in this issue 1 is a timely and important contribution to the ocular examination and management of the retinopathy in these premature infants. See also p... more
The international classification of acute retinopathy of prematurity (ROP) appearing in this issue 1 is a timely and important contribution to the ocular examination and management of the retinopathy in these premature infants. See also p 1130. During the epidemic period of ROP, generally designated then as retrolental fibroplasia, the survival rate of small premature neonates with birthweights under 1,000 g was less than 10%. By the 1980s, due to improved neonatal care, that survival rate has increased by fourfold or greater. These low-birthweight infants, who are at the highest risk of ROP, are surviving today, but in the early 1950s would not have lived long enough for the disease to develop. Cases of ROP are occurring today despite the most meticulous monitoring of arterial blood gases. The extreme prematurity, combined with factors other than excess oxygen, may be responsible for current cases. With a substantial number of new cases
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The safest ranges of oxygen saturation in preterm infants have been the subject of debate. In two trials, conducted in Australia and the United Kingdom, infants born before 28 weeks' gestation were randomly assigned to either a lower... more
The safest ranges of oxygen saturation in preterm infants have been the subject of debate. In two trials, conducted in Australia and the United Kingdom, infants born before 28 weeks' gestation were randomly assigned to either a lower (85 to 89%) or a higher (91 to 95%) oxygen-saturation range. During enrollment, the oximeters were revised to correct a calibration-algorithm artifact. The primary outcome was death or disability at a corrected gestational age of 2 years; this outcome was evaluated among infants whose oxygen saturation was measured with any study oximeter in the Australian trial and those whose oxygen saturation was measured with a revised oximeter in the U.K. trial. After 1135 infants in Australia and 973 infants in the United Kingdom had been enrolled in the trial, an interim analysis showed increased mortality at a corrected gestational age of 36 weeks, and enrollment was stopped. Death or disability in the Australian trial (with all oximeters included) occurred ...
Research Interests: Internal Medicine (General Medicine), Australia, Risk, General Internal Medicine, Medicine, and 15 moreHumans, Female, Male, Social and Behavioral Sciences, Infant, Developmental disabilities, Newborn Infant, Great Britain, Oxygen, Infant Mortality, Oximetry, Medicine and Health Sciences, New England Journalof Medicine, Child preschool, and Medical and Health Sciences
Research Interests: Epidemiology, Medicine, Visual acuity, Humans, Queensland, and 15 moreFemale, Male, Incidence, Risk factors, Rupture, Clinical Sciences, Optometry and Ophthalmology, Adult, Public health systems and services research, Retrospective Studies, Risk Factors, Clinical and Experimental Hypnosis, Occupations, Clinical and Experimental Ophthalmology, and Indian Journal of Clinical and Experimental Ophthalmology
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The objective of this review was to identify and describe telehealth models of care for ophthalmic services. We conducted a scoping review of the literature to identify how ophthalmic care can be delivered by telehealth. We searched the... more
The objective of this review was to identify and describe telehealth models of care for ophthalmic services. We conducted a scoping review of the literature to identify how ophthalmic care can be delivered by telehealth. We searched the PubMed database to identify relevant articles which were screened based on pre-defined inclusion criteria. For included articles, data were extracted, categorised and analysed. Synthesis of findings was performed narratively. The scoping review included 78 articles describing 62 discrete tele-ophthalmic models of care. Tele-ophthalmic models of care can be used for consultative service, screening, triage and remote supervision. The majority of services were for general eye care and triage ( n = 17; 26%) or emergency services ( n = 8; 12%). The most common conditions for disease-specific models of care were diabetic retinopathy ( n = 14; 21%), and glaucoma ( n = 8; 12%). Most models of care involved local clinicians capturing images and transmitting t...
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The Accreditation Council for Graduate Medical Education (ACGME) requires US residency programs to assess ophthalmology residents for competency in 6 core areas. Ophthalmic surgical skills are currently part of the ACGME "Patient... more
The Accreditation Council for Graduate Medical Education (ACGME) requires US residency programs to assess ophthalmology residents for competency in 6 core areas. Ophthalmic surgical skills are currently part of the ACGME "Patient Care" competency, although some have advocated for a seventh competency, "Surgical Skills." The Ophthalmology Surgical Competency Assessment Rubric for Strabismus Surgery in Resident Training ( Strabismus) tool was designed to aid in the assessment of surgical skills using procedure specific behavioral anchors. The present study evaluated inter-rater agreement of the Strabismus tool in the assessment of resident performance. Strabismus evaluations of resident surgical strabismus cases were performed by a multinational group of faculty strabismus surgeons. Cronbach α statistical analysis of the completed evaluations revealed high inter-rater agreement, indicating the Strabismus is a reliable tool to facilitate assessment of resident strab...
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Oxygen-induced retinopathy was produced by exposing 3-day-old kittens to 80% oxygen between 60 and 105 hours. They were then allowed to survive in room air until day 15, 21 or 28 when they were sacrificed after perfusion with colloidal... more
Oxygen-induced retinopathy was produced by exposing 3-day-old kittens to 80% oxygen between 60 and 105 hours. They were then allowed to survive in room air until day 15, 21 or 28 when they were sacrificed after perfusion with colloidal carbon. Specimens were prepared for transmission electron microscopy. Ninety separate vitreous capillaries from oxygen-treated animals were examined. A total of 235 intercellular junctions were examined, 116 of them from the 15-day old animals. In the 15-day old animals, five junctions of 116 were open and the remainder were tight. No open junctions were seen in 21- or 28-day-old animals. In one capillary from a 15-day animal, fenestrated endothelium was seen in an aberrant, intraluminal loop of endothelium which formed no part of the blood/tissue barrier. The wall thickness of the vitreous new vessels seemed to decrease and the number of vesicles and vacuoles appeared to increase with increasing age. The basement membrane of the vitreous new vessels was scanty. In some sections, cells, presumably macrophages, were seen outside the new vessels. It is concluded that the increased permeability of the vitreous new vessels in 15-day-old animals can be explained by, and is possibly totally due to, the presence of open endothelial junctions.
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Changes to the redox status of biological systems have been implicated in the pathogenesis of a wide variety of disorders including cancer, Ischemia-reperfusion (I/R) injury and neurodegeneration. In times of metabolic stress e.g.... more
Changes to the redox status of biological systems have been implicated in the pathogenesis of a wide variety of disorders including cancer, Ischemia-reperfusion (I/R) injury and neurodegeneration. In times of metabolic stress e.g. ischaemia/reperfusion, reactive oxygen species (ROS) production overwhelms the intrinsic antioxidant capacity of the cell, damaging vital cellular components. The ability to quantify ROS changes in vivo, is therefore essential to understanding their biological role. Here we evaluate the suitability of a novel reversible profluorescent probe containing a redox-sensitive nitroxide moiety (methyl ester tetraethylrhodamine nitroxide, ME-TRN), as an in vivo, real-time reporter of retinal oxidative status. The reversible nature of the probe's response offers the unique advantage of being able to monitor redox changes in both oxidizing and reducing directions in real time. After intravitreal administration of the ME-TRN probe, we induced ROS production in rat...
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We have examined the feasibility of a telemedicine-enabled screening service for children and adolescents with diabetes in Queensland. There are approximately 1400 young people with diabetes in Queensland and only about two-thirds of them... more
We have examined the feasibility of a telemedicine-enabled screening service for children and adolescents with diabetes in Queensland. There are approximately 1400 young people with diabetes in Queensland and only about two-thirds of them are screened in accordance with international guidelines. A regional retinal screening service was established using a nonmydriatic digital retinal camera. Seven centres volunteered to participate in the study. During a five-month pilot trial, 83 of the young people with diabetes who attend these centres underwent digital retinal screening (3.7%). Retinal images were sent via email to a paediatric ophthalmologist for review and results were returned via email. A copy of each participant's results was forwarded by mail to the referring diabetes doctor and the participant and family. The majority of the image files (96%) were rated as excellent or good. Only one participant was identified as having an abnormal result. Participants and their famil...
Research Interests: Information Systems, Biomedical Engineering, Health Services Research, Adolescent, Telemedicine, and 12 moreYoung People, Humans, Child, Queensland, Diabetic Retinopathy, Female, Feasibility Studies, Male, Patient Satisfaction, Public health systems and services research, Type 2 Diabetes Mellitus, and mass Screening
Retinoblastoma is the commonest intraocular tumour of childhood with the majority of cases being diagnosed before 5 years of age. Late presentation of retinoblastoma is rare. A healthy 16-year-old Caucasian girl presented with a 1-day... more
Retinoblastoma is the commonest intraocular tumour of childhood with the majority of cases being diagnosed before 5 years of age. Late presentation of retinoblastoma is rare. A healthy 16-year-old Caucasian girl presented with a 1-day history of blurred vision in the left eye. Examination revealed an inferonasal mass in the left retina with an overlying haemorrhage and vitreous seeding. Imaging studies revealed a 5-mm densely calcified opacity. Other investigations, including cerebral spinal fluid examination, bone marrow aspirate trephine, toxocara serology and serum protein studies, were normal. After considering the differential diagnoses such as toxocariasis and Coat's disease, a diagnosis of late-presenting retinoblastoma was made. The patient subsequently underwent enucleation with a primary orbital implant. The diagnosis was confirmed histopathologically. Late presentation of retinoblastoma is uncommon but can be a cause of acute visual impairment in the non-paediatric ag...
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Capillary haemangiomas are vascular tumours of childhood characterised by proliferative and involutional phases and affecting 1% to 2% of newborns. Recently, recombinant interferons have been used in the treatment of life and sight... more
Capillary haemangiomas are vascular tumours of childhood characterised by proliferative and involutional phases and affecting 1% to 2% of newborns. Recently, recombinant interferons have been used in the treatment of life and sight threatening complications of these tumours. The history, results of examination, investigations, management and outcome of two patients with sight-threatening orbital capillary haemangiomas treated with recombinant interferon alpha-2a and 2b respectively were reviewed. Orbital and systemic lesions displayed good response to interferons. Side effects noted were transient pyrexia and elevated serum aminotransferase levels. Disturbed liver function test results occurred in one case and normalised with temporary cessation of therapy. The interferons are a useful alternative treatment of orbital capillary haemangioma in selected cases.
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Many techniques have been described for the detection of functional visual loss. We report four cases in which Ishihara pseudo-isochromatic colour plates gave objective evidence of functional vision loss. In all cases the patients were... more
Many techniques have been described for the detection of functional visual loss. We report four cases in which Ishihara pseudo-isochromatic colour plates gave objective evidence of functional vision loss. In all cases the patients were able to read the first test pattern (No. 12), but could not distinguish any of the following pseudo-isochromatic numbers (plates 2-17). However, they experienced no difficulty in tracing the winding lines (plates 18-24), demonstrating that they in fact had normal colour vision.
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We have studied the kitten model of oxygen induced retinopathy by the technique of corrosion vascular casting/scanning electron microscopy. The predominant morphological features of the kitten model are preretinal and intraretinal... more
We have studied the kitten model of oxygen induced retinopathy by the technique of corrosion vascular casting/scanning electron microscopy. The predominant morphological features of the kitten model are preretinal and intraretinal neovascularization with a minor component of arterio-venous shunting. This is contrasted with the active phase of the blinding disease in the human neonate which is characterised predominantly by so called 'mesenchymal arterio-venous shunting'. A failure to appreciate fundamental differences in the nature of oxygen induced retinopathy between the human infant and its kitten model we believe has led to erroneous conclusions about pathogenesis in the human neonate.
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Forced-choice preferential looking (FPL) is a behavioural technique for the estimation of visual acuity in preverbal children. We have constructed an electromechanical FPL apparatus controlled by a microprocessor requiring just one... more
Forced-choice preferential looking (FPL) is a behavioural technique for the estimation of visual acuity in preverbal children. We have constructed an electromechanical FPL apparatus controlled by a microprocessor requiring just one operator. Sixty-three babies aged between six weeks and eleven months were evaluated with an overall success rate of 83% in obtaining an acuity measurement. FPL is a practical method for measurement of infant visual acuity in the ophthalmic clinic setting.
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Combined hamartoma of the retina and retinal pigment epithelium (RPE), is a rare, benign, congenital fundal lesion which contains a mixture of glial tissue, blood vessels and pigment epithelium. Such tumours are variably pigmented and may... more
Combined hamartoma of the retina and retinal pigment epithelium (RPE), is a rare, benign, congenital fundal lesion which contains a mixture of glial tissue, blood vessels and pigment epithelium. Such tumours are variably pigmented and may be wrongly diagnosed as malignant melanoma or retinoblastoma. We report two cases which were located in the periphery of the fundus and which produced a dragged disc appearance.
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Laminin is a basement membrane glycoprotein, widely distributed in body tissues. It has been found on capillary basement membranes in both developing and adult retinal vessels. Oxygen-induced retinopathy was produced in kittens and mice... more
Laminin is a basement membrane glycoprotein, widely distributed in body tissues. It has been found on capillary basement membranes in both developing and adult retinal vessels. Oxygen-induced retinopathy was produced in kittens and mice by exposing them to a high oxygen environment during the newborn period. When the animals developed a proliferative retinopathy after a period of survival in room air, they were sacrificed and the eyes enucleated and embedded in paraffin wax. Cross-sections were cut and de-waxed. After preliminary digestion with pepsin, we used a fluorescein isothiocyanate (FITC)-labelled double antibody technique to identify laminin-like immunoreactivity (LLIR). LLIR was found on both intravitreal and intraretinal new vessels in the kitten and mouse, indicating that it is probably secreted by endothelial cells during the formation of pathological new vessels.
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A 78-year-old man with perifoveal subretinal neovascularization originally treated with krypton red laser was re-treated. An attempt was made to produce a "chalky white" burn at the site of the neovascular frond. Immediately... more
A 78-year-old man with perifoveal subretinal neovascularization originally treated with krypton red laser was re-treated. An attempt was made to produce a "chalky white" burn at the site of the neovascular frond. Immediately after a burn, a brisk choroidal haemorrhage followed, apparently from a ruptured choroidal vessel. Bleeding occurred subretinally and into the vitreous, blinding the patient. While the krypton red laser carries advantages over the argon laser in the treatment of subretinal neovascular fronds, this case indicates that hard burns with the krypton laser carry a risk of massive subretinal haemorrhage.
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To establish the sensitivity and specificity of the Bruckner reflex (comparison of the fundus red reflexes) in the detection of amblyopia or its risk factors. A single masked study using a medical student's diagnostic ability... more
To establish the sensitivity and specificity of the Bruckner reflex (comparison of the fundus red reflexes) in the detection of amblyopia or its risk factors. A single masked study using a medical student's diagnostic ability against the gold standard of a full clinical examination by a paediatric ophthalmologist. A university teaching hospital outpatient facility. Three hundred and one patients consecutively referred for ophthalmic assessment. The sensitivity of the test for the detection of children with amblyopia risk factors was 86% and the specificity was 65%. Of 70 children with a definite diagnosis of amblyopia, the sensitivity of the test was 95%. The Bruckner reflex is a useful screening test for primary eye care personnel. However, there is a significant false-positive rate which will result in unnecessary referrals. We recommend that it form part of a battery of tests, including, for example, the modified base down prism test, which are useful in assessing the vision of preverbal children.
Research Interests: Australian and New Zealand Cinema, Adolescent, Amblyopia, Humans, Child, and 12 moreInfant, Risk factors, Clinical Sciences, Optometry and Ophthalmology, Public health systems and services research, Reflex, Reproducibility of Results, Risk Factors, Sensitivity and Specificity, Predictive value of tests, Ophthalmoscopy, and Child preschool
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A two year study of one hundred and forty five cataract extractions showed a 38% incidence of post operative macular oedema. The leak had resolved in most cases by six months and the only factor of significance in the production of the... more
A two year study of one hundred and forty five cataract extractions showed a 38% incidence of post operative macular oedema. The leak had resolved in most cases by six months and the only factor of significance in the production of the oedema was preoperative hypertension. The likelihood of obtaining 6/6 vision postoperatively was much lessened in the presence of macular oedema.
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Eccentric photorefraction (EPR) is a simple photographic technique for detecting amblyopiogenic conditions. Previous EPR studies to detect refractive errors (RE) have demonstrated high sensitivity but poor predictive value. We have... more
Eccentric photorefraction (EPR) is a simple photographic technique for detecting amblyopiogenic conditions. Previous EPR studies to detect refractive errors (RE) have demonstrated high sensitivity but poor predictive value. We have established new criteria for detecting RE involving quantifying retinoscopic reflex crescent widths, thereby achieving 67% predictive value with 100% sensitivity for detecting RE greater than or equal to +3.5 D in a clinical study of 69 children. Optical analysis of EPR shows that anticrescent width (light crescent-free portion of the pupil) is independent of pupil diameter. Quantifying anticrescent widths in the above clinical trial increased the predictive value to 85%. Schematic eye and human eye EPR studies verify the theoretical prediction that similar ability to detect refractive errors is maintained when the working distance and eccentricity (distance of light source from lens edge) are reduced. These improvements in EPR reduce its cost and improve its yield; both are essential for its introduction as an acceptable community screening tool.
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In an investigation of the psychosocial impact of amblyopia on children, the perceived self-esteem of children who had been treated for amblyopia was compared with that of age-matched controls. The influence of amblyopia condition or... more
In an investigation of the psychosocial impact of amblyopia on children, the perceived self-esteem of children who had been treated for amblyopia was compared with that of age-matched controls. The influence of amblyopia condition or treatment factors that may impact self-perception scores was also explored. Children with a history of treatment for amblyopia (n = 47; age 9.2 +/- 1.3 years) and age-matched controls (n = 52; age 9.4 +/- 0.5 years) completed a standardized age-appropriate questionnaire based evaluation of perceived self-esteem (Harter Self Perception Profile for Children). Their vision characteristics and treatment regimen were also recorded. Bivariate correlation analysis was used to investigate the amblyopic characteristics and treatment factors that may have influenced self-perception scores in the amblyopic group. Children treated for amblyopia had significantly lower social acceptance scores than age-matched control children. In other areas related to self-esteem, including scholastic competence, physical appearance, athletic competence, behavioral conduct and global self worth, amblyopic children gave scores similar to those of control children. Within the amblyopic group, a lower social acceptance score was significantly correlated with a history of treatment with patching but not with a history of strabismus or wearing of glasses. Self-perception of social acceptance was lower in children treated for amblyopia compared with age-matched controls. A reduction in these scores was associated with a history of patching treatment but not with a history of strabismus or spectacle wear.
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To investigate the functional impact of amblyopia in children, the performance of amblyopic and age-matched control children on a clinical test of eye movements was compared. The influence of visual factors on test outcome measures was... more
To investigate the functional impact of amblyopia in children, the performance of amblyopic and age-matched control children on a clinical test of eye movements was compared. The influence of visual factors on test outcome measures was explored. Eye movements were assessed with the Developmental Eye Movement (DEM) test, in a group of children with amblyopia (n = 39; age, 9.1 +/- 0.9 years) of different causes (infantile esotropia, n = 7; acquired strabismus, n = 10; anisometropia, n = 8; mixed, n = 8; deprivation, n = 6) and in an age-matched control group (n = 42; age, 9.3 +/- 0.4 years). LogMAR visual acuity (VA), stereoacuity, and refractive error were also recorded in both groups. No significant difference was found between the amblyopic and age-matched control group for any of the outcome measures of the DEM (vertical time, horizontal time, number of errors and ratio(horizontal time/vertical time)). The DEM measures were not significantly related to VA in either eye, level of binocular function (stereoacuity), history of strabismus, or refractive error. The performance of amblyopic children on the DEM, a commonly used clinical measure of eye movements, has not previously been reported. Under habitual binocular viewing conditions, amblyopia has no effect on DEM outcome scores despite significant impairment of binocular vision and decreased VA in both the better and worse eye.
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Research Interests: Ophthalmology, Optical coherence tomography, Amblyopia, Visual acuity, Humans, and 14 moreChild, Optic Nerve, Female, Male, New South Wales, Clinical Sciences, Eye, Questionnaires, Optometry and Ophthalmology, Public health systems and services research, Retinal Ganglion Cells, Cross Sectional Studies, Nino, and Macula lutea
In this study we examine neuroretinal function in five amblyopes, who had been shown in previous functional MRI (fMRI) studies to have compromised function of the lateral geniculate nucleus (LGN), to determine if the fMRI deficit in... more
In this study we examine neuroretinal function in five amblyopes, who had been shown in previous functional MRI (fMRI) studies to have compromised function of the lateral geniculate nucleus (LGN), to determine if the fMRI deficit in amblyopia may have its origin at the retinal level. We used slow flash multifocal ERG (mfERG) and compared averaged five ring responses of the amblyopic and fellow eyes across a 35 deg field. Central responses were also assessed over a field which was about 6.3 deg in diameter. We measured central retinal thickness using optical coherence tomography. Central fields were measured using the MP1-Microperimeter which also assesses ocular fixation during perimetry. MfERG data were compared with fMRI results from a previous study. Amblyopic eyes had reduced response density amplitudes (first major negative to first positive (N1-P1) responses) for the central and paracentral retina (up to 18 deg diameter) but not for the mid-periphery (from 18 to 35 deg). Retinal thickness was within normal limits for all eyes, and not different between amblyopic and fellow eyes. Fixation was maintained within the central 4° more than 80% of the time by four of the five participants; fixation assessed using bivariate contour ellipse areas (BCEA) gave rankings similar to those of the MP-1 system. There was no significant relationship between BCEA and mfERG response for either amblyopic or fellow eye. There was no significant relationship between the central mfERG eye response difference and the selective blood oxygen level dependent (BOLD) LGN eye response difference previously seen in these participants. Retinal responses in amblyopes can be reduced within the central field without an obvious anatomical basis. Additionally, this retinal deficit may not be the reason why the LGN BOLD (blood oxygen level dependent) responses are reduced for amblyopic eye stimulation.